Atmospheric new particle formation (NPF) is an important global phenomenon that is nevertheless sensitive to ambient conditions. According to both observation and theoretical arguments, NPF usually ...requires a relatively high sulfuric acid (H
SO
) concentration to promote the formation of new particles and a low preexisting aerosol loading to minimize the sink of new particles. We investigated NPF in Shanghai and were able to observe both precursor vapors (H
SO
) and initial clusters at a molecular level in a megacity. High NPF rates were observed to coincide with several familiar markers suggestive of H
SO
-dimethylamine (DMA)-water (H
O) nucleation, including sulfuric acid dimers and H
SO
-DMA clusters. In a cluster kinetics simulation, the observed concentration of sulfuric acid was high enough to explain the particle growth to ~3 nanometers under the very high condensation sink, whereas the subsequent higher growth rate beyond this size is believed to result from the added contribution of condensing organic species. These findings will help in understanding urban NPF and its air quality and climate effects, as well as in formulating policies to mitigate secondary particle formation in China.
The aim of this research is to study the effect of body overweight at birth (fetal macrosomia) on the processes of tooth eruption and tooth growth during the first year of life in children in the ...Kharkiv City (Ukraine) population. One of the research tasks is to examine the features of deciduous teeth eruption in children who were born with macrosomia with different values of the weight-height index at birth. Materials and methods. The medical records of the children born between 1977 and 2013 have been analyzed. The database has been collected in one of the Kharkiv City clinic. The Main Group is comprised of the medical records of the children (separately for boys and girls) born with fetal macrosomia. All the medical records of the Main Group have been divided into subgroups taking into account the gender and the harmonious (well-balanced) development coefficient. The Comparison Group is comprised of the medical records of the children also born within the normal term range, but with weight and height that correspond to the gestation age (fetal normosomia). To determine the average time of the first tooth eruption, as well as the deciduous teeth growth rate for each of the groups under the study, we have used the hypothesis about a linear dependence between the number of erupted teeth and the age of the child. The statistical data processing and verification of the consistency of this hypothesis is performed using the multiple linear regression analysis with the STATISTICA 6.0 software package (Multiple Regression module). The number of delayed eruption and premature eruption cases observed is calculated along with the corresponding confidence intervals for the significance level, p, of less than 0.05, taking into account the binomial distribution of the random variable. The results of the study indicate a slowed growth rate of deciduous teeth in children born with macrosomia, as well as an increased number of cases (by a factor of 2 to 4 times) of deviations in the timing of teeth eruption compared to regional norms. The smallest growth rate of deciduous teeth and the smallest number of teeth at the age of one year are registered in macrosomic boys and macrosomic girls with a long body and a relatively reduced birth weight, as well as in macrosomic girls with intrauterine obesity. The macrosomic girls with intrauterine acceleration with obesity at the background have the largest average tooth growth rate and the largest percentage of premature eruption cases among all subgroups. Conclusions. The somatometric features of fetal macrosomia suggest the influence on the number of teeth that erupt by a certain age. The data on the deviation from the generally accepted terms of teeth eruption in children born with macrosomia, can be the basis for developing new and improving existing prevention programs aimed at preserving dental health.
The oxidation of aromatics contributes significantly to the formation of atmospheric aerosol. Using toluene as an example, we demonstrate the existence of a molecular rearrangement channel in the ...oxidation mechanism. Based on both flow reactor experiments and quantum chemical calculations, we show that the bicyclic peroxy radicals (BPRs) formed in OH-initiated aromatic oxidation are much less stable than previously thought, and in the case of the toluene derived ipso-BPRs, lead to aerosol-forming low-volatility products with up to 9 oxygen atoms on sub-second timescales. Similar results are predicted for ipso-BPRs formed from many other aromatic compounds. This reaction class is likely a key route for atmospheric aerosol formation, and including the molecular rearrangement of BPRs may be vital for accurate chemical modeling of the atmosphere.
Oxidation chemistry controls both combustion processes and the atmospheric transformation of volatile emissions. In combustion engines, radical species undergo isomerization reactions that allow fast ...addition of O
. This chain reaction, termed autoxidation, is enabled by high engine temperatures, but has recently been also identified as an important source for highly oxygenated species in the atmosphere, forming organic aerosol. Conventional knowledge suggests that atmospheric autoxidation requires suitable structural features, like double bonds or oxygen-containing moieties, in the precursors. With neither of these functionalities, alkanes, the primary fuel type in combustion engines and an important class of urban trace gases, are thought to have minor susceptibility to extensive autoxidation. Here, utilizing state-of-the-art mass spectrometry, measuring both radicals and oxidation products, we show that alkanes undergo autoxidation much more efficiently than previously thought, both under atmospheric and combustion conditions. Even at high concentrations of NO
, which typically rapidly terminates autoxidation in urban areas, the studied C
-C
alkanes produce considerable amounts of highly oxygenated products that can contribute to urban organic aerosol. The results of this inter-disciplinary effort provide crucial information on oxidation processes in both combustion engines and the atmosphere, with direct implications for engine efficiency and urban air quality.
Introduction: The prevalence of soft tissue and hard tooth tissuediseases in the oral cavity and the morphofunctional disorders of craniofacial complex, require attention ofspecialistsin various ...branches of medicine. Scientists began to pay attention to metabolic and other violations that have occurred in the fetal development and led to the occurrence of certain changes in the dental status of the child. The aim of this research is to study the features of the dental health condition in the children of Northeast of Ukraine, who were born with macrosomia during the period of mixed dentition. The study takes into account intrauterine body length growth acceleration, intrauterine obesity or well-balanced acceleration of both the body weight and length gain.
Materials and methods:Thirty 6.5-11-year-old children with fetal macrosomia were examined (MainGroup). A Comparison Group was comprised of sixteen children, whose weight-height parameters at birth were normal (fetal normosomia). All children in the Main group were split into four subgroups in accordance with weight-height parameters at birth using the V. I. Grischenko and his co-authors' harmonious coefficient. The evaluation of the hygiene status of the oral cavity, the dental caries intensity evaluation, and the quantitative analysis of minor salivary gland secretion have been performed. The prevalence of dentoalveolar abnormalities was evaluated.
Results: The highest values of caries intensity were recorded in macrosomic-at-birth children born with harmonious (well-balanced) intrauterine development, with intrauterine obesity and increased body length, or with intrauterine obesity and an average body length. Macrosomic children have reduced number of minor salivary glands per unit area in comparison with the normosomic-at-birth children. The saliva secretion of minor salivary glands in macrosomic children is reliably, by 16,5% on average, reduced. Children born with fetal macrosomia have long narrow faces and high palates more frequently than normosomic-at-birth children. Children born macrosomic have a significantly higher percentage (100% versus 73%)of dentoalveolar abnormalitiesin comparison with the normosomic-at-birth children.
Conclusions: The processes causing fetal macrosomia have a great impact on the dental status of children in the period of mixed dentition.
Abstract
Siberia is covered by 6 million km
2
of forest, which moderates climate as a carbon sink and a source of aerosol particles causing negative radiative effect. Aerosol particles in boreal ...forests frequently form via gas-to-particle conversion, known as new particle formation (NPF). Compared to boreal sites at similar latitudes, NPF was reported to occur less often in the Siberian forest. However, factors controlling NPF in Siberia remain unknown. Our results suggest that the combination of biogenic and anthropogenic contributions caused unexpectedly high monthly NPF frequency (50%) at the observatory Fonovaya in the West Siberian taiga during the Siberian 2020 heatwave. High frequency was due to early spring photosynthetic recovery, which boosted biogenic emissions into polluted air masses carrying SO
2
. After mid-April, high temperatures and cleaner air masses led to less frequent (15%) and less intense NPF despite the increased emissions of natural organic vapors and ammonia. Furthermore, the contrast between the two spring periods was seen in cluster composition, particle-forming vapors (two times difference in sulfuric acid concentration), particle formation (
J
3
, 2.2 and 0.4 cm
−3
s
−1
) and growth rates (GR
2−3
, 1.7 and 0.6 nm h
−1
). Given the strong warming trend, our results suggest that within 25‒30 years, the monthly NPF frequency during early spring in the West Siberian taiga can reach 40%–60%, as in the European boreal sites.
A 37 m deep ice core representing 1957–2009 and snow from 2009 to 2010 were collected on the Lomonosovfonna glacier, Svalbard (78.82° N; 17.43° E) and analyzed for 209 polychlorinated biphenyl (PCB) ...congeners using high-resolution mass spectrometry. Congener profiles in all samples showed the prevalence of tetra- and pentachlorobiphenyls, dominated in all samples by PCB-44, PCB-52, PCB-70 + PCB-74, PCB-87 + PCB-97, PCB-95, PCB-99, PCB-101, and PCB-110. The ∑PCB flux varied over time, but the peak flux, ∼19 pg cm–2 year–1 from 1957 to 1966, recurred in 1974–1983, 1998–2009, and 2009–2010. The minimum was 5.75 pg cm–2 year–1 in 1989–1998, following a 15 year decline. Peak ∑PCB fluxes here are lower than measured in the Canadian Arctic. The analysis of all 209 congeners revealed that PCB-11 (3,3′-dichlorobiphenyl) was present in all samples, representing 0.9–4.5% of ∑PCB. PCB-11 was not produced in a commercial PCB product, and its source to the Arctic has not been well-characterized; however, our results confirm that the sources to Lomonosovfonna have been active since 1957. The higher fluxes of ∑PCB correspond to periods when average 5 day air mass back trajectories have a frequency of 8–10% and reach 60° N or beyond over northern Europe and western Russia or the North Sea into the U.K.
The aim: The article deals with analyzing the influence of polymorphic variants of CYP19A1 rs2414096, rs936306, ESR1 rs2234693, rs9340799, IL1 rs1143627, IL6 rs1800796, IL10 rs1800896 and RANKL ...rs959389 genes on deciduous tooth eruption terms in individuals born macrosomic.
Materials and methods: 171 individuals participated in the multi-stage study (144 macosomic-at-birth individuals and 27 normosomic-at-birth persons). This study included only persons who have preserved information about the timing of deciduous tooth eruption - 159 persons (aged from 4 to 55 years), male and female (male / female ratio was 1.5 / 1).
Results and conclusions: The presence of the G allele in CYP19A1 rs2414096 gene and the -351 A allele in ESR1 rs9340799 gene were found to be risk factors for fetal macrosomia formation. The research revealed an association of RANKL rs9594759 gene variants which is a multiplicative model of inheritance and IL-10 rs1800896, an overdominant model of inheritance, with an increased risk of tooth delay. Besides the variants of RANKL rs9594759 and IL-10 rs1800896 genes a multidirectional modifying effect on the timing of tooth eruption in macrosomic-at-birth individuals made the variant of CYP19A1 rs2414096 gene - a significant dominant and over-dominant model of inheritance. Further analysis of intergenic interactions will facilitate the application of the obtained results in clinical practice by creating a molecular profile of individuals with deviations in the tooth eruption timing.
We examined the histological features of the mucobuccal fold of oral cavity mucous membrane from the area of the masticatory teeth roots' projection in 6-month-old Wistar Albino Glaxo rats with fetal ...macrosomia. The animals were divided into groups according to the body weight, the body length, and the Quetelet index at birth. A morphological study was performed using the Leica SP8 AOBS laser scanning confocal microscope and a conventional light (Axiostar, Zeiss) microscopy. Morphometric parameters were used to estimate the degree of acanthosis development in the epithelium of the oral mucosa, which indicates the intensity of its proliferation. Numerous narrow and deep acanthotic outgrowths and densely located 'juvenile' epitheliocytes in the basal layer on the apex of the acanthotic protrusions were found in animals with fetal macrosomia that was due to intrauterine obesity. In these animals, the morphometric index, which we used, was maximally different from that in the control group. In animals with fetal macrosomia that was due to intrauterine growth acceleration of the body, the hyperproliferation of the mucous membrane epithelium of the oral cavity was absent or little pronounced. It can be assumed that fetal macrocosmia with obesity causes instability in the epithelium of the oral cavity mucosa, its rapid death, and therefore, a more active stimulation of proliferation.
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